Sweet MAO

ABSTRACT

Aluminoxanes are used as activators for the gas, solution or slurry phase polymerization of olefins in the presence of single site catalysts. Aluminoxanes contain residual aluminum alkyls which may poison the catalysts. The residual aluminum alkyls may be bound an/or removed from the aluminoxanes by treatment with carbohydrates such as cellulose, starch or sugar.

FIELD OF THE INVENTION

[0001] The present invention relates to activators for polymerizationcatalysts. More particularly the present invention relates toaluminoxane (or alumoxane or polyaluminum oxide) activators which havebeen treated with a carbohydrate prior to use as activators forpolymerization catalysts such as single site catalysts. The presentinvention also relates to catalyst systems activated with such treatedaluminum compounds and to polymerization processes using such treatedaluminum compounds.

BACKGROUND OF THE INVENTION

[0002] Aluminoxane compounds are known in the art. Generally suchcompounds may be characterized by the formula I: R⁴ ₂AlO(R⁴AlO)_(m)AlR⁴₂ wherein each R⁴ is independently selected from the group consisting ofC₁₋₂₀ hydrocarbyl radicals and m is from 3 to 50, preferably from 5 to30. Aluminoxane compounds have found use in the polymerization of olefinmonomers with single site catalysts such as the bis Cp-type catalyststaught by Exxon Chemical Patents Inc. in a number of patents includingfor example those by Welborn, Jr., Turner, Hlatky and Canich. The DowChemical Company has a number of patents claiming constrained geometrycatalysts having a single Cp ligand bridged, typically by a silylbridge, to another ligand, typically an amido ligand. NOVA Chemicals hasfiled patents claiming the use of unbridged phosphinimine complexes andketimide complexes as polymerization catalysts as disclosed by patentsin the names of Stephan, Brown, McMeeking, Gao, Spence and Wang. TheUniversity of Alberta also has also a number of patents claiming the useof phosphinimine catalysts for the polymerization of olefins such asthose in the name of Cavell.

[0003] All of the above catalysts may be activated with aluminoxanes orMAO if R⁴ is a methyl radical. In recent years there have been a numberof variants of MAO.

[0004] U.S. Pat. No. 5,547,675 issued Aug. 20, 1996 to Canich, assignedto Exxon Chemical Patents Inc. teaches a catalyst system comprising amono Cp single site catalyst, an aluminoxane and a modifier. Themodifier is a Lewis base or a compound containing one or more Lewis basefunctionalities which are capable of reacting with a Lewis acid such astrimethyl aluminum. A number of representative compounds are thendisclosed in the disclosure. The disclosure does not suggest thatcarbohydrates would be suitable compounds to react with aluminoxanes.

[0005] Of interest is U.S. Pat. No. 4,431,788 issued Feb. 14, 1984 toKaminsky, assigned to CPC International Inc. This patent does notdisclose MAO per se. However, the patent discloses a process for makinga starch/polyolefin composition by polymerizing the olefin monomer(s)with a cyclopentadienyl containing transition metal catalyst and starchwhich has been contacted with aluminum trialkyl. The patent does notsuggest treating MAO with starch.

[0006] The present invention seeks to provide a relatively lower costalternative to improving the reactivity of aluminoxane than thatdisclosed in the prior art.

SUMMARY OF THE INVENTION

[0007] The present invention provides a process comprising treating acomplex aluminum compound of the formula R⁴ ₂AlO(R⁴AlO)_(m)AlR⁴ ₂wherein each R⁴ is independently selected from the group consisting ofC₁₋₂₀ hydrocarbyl radicals and m is from 3 to 50, with one or morecarbohydrates in a weight ratio of aluminum complex to carbohydrate from1:100 to 100:1 at a temperature from 0° C. to 200° C. for a time of atleast 5 minutes.

[0008] In a further aspect, the present invention provides a catalystsystem comprising a transition metal complex in the presence of anactivator comprising an aluminum complex of the formula R⁴₂AlO(R⁴AlO)_(m)AlR⁴ ₂ wherein each R⁴ is independently selected from thegroup consisting of C₁₋₂₀ hydrocarbyl radicals and m is from 3 to 50which has been treated with one or more carbohydrates in a weight ratioof aluminum complex to carbohydrate from 1:100 to 100:1 at a temperaturefrom 0° C. to 200° C., to provide a molar ratio of treated aluminum totransition metal from 5:1 to 1000:1.

[0009] In a further embodiment, the present invention provides a processfor the polymerization of one or more olefins at a temperature from 50°C. to 250° C. in the presence of the above catalyst system.

BEST MODE

[0010] Aluminoxane compounds of the present invention have the formulaI: R⁴ ₂AlO(R⁴AlO)_(m)AlR⁴ ₂ wherein each R⁴ is independently selectedfrom the group consisting of C₁₋₂₀ hydrocarbyl radicals and m is from 3to 50, preferably from 5 to 30. Most preferably R⁴ is selected from thegroup consisting of C₁₋₆, most preferably C₁₋₄ straight chained orbranched alkyl radicals. Suitable alkyl radicals include a methylradical, an ethyl radical, an isopropyl radical and an isobutyl radical.In some commercially available aluminoxanes R⁴ is a methyl radical.

[0011] Carbohydrates comprise a broad class of organic chemicalstypically having the empirical formula (CH₂O)_(n). Carbohydrates may bemonosaccharides, disaccharides, oligosaccharides and polysaccharides.

[0012] Typically the monosaccharides are polyhydroxy aldehydes orketones or derivatives thereof. Typical monosaccharides comprise from 3to 6 carbon atoms (C₃₋₆) polyhydroxy aldehydes or ketones (i.e. n is 3to 6). The higher carbon monosaccharides, having 4 or more carbon atoms,may also form ring structures. The monosaccharides have chiral centersand have D- and L- forms. Some of the common monosaccharides includeglyceraldehyde, erythrose, thresoe, arabinose, ribose, lyxose, xylose,glucose, mannose, altrose, allose, talose, galactose, idose and gluose.The five and six membered rings may be referred to as furanose andpyranose based on the parent ring structure of either furan (5-memberedcyclic ether) or pyran (6-membered cyclic ether).

[0013] As the monosaccharides have multiple hydroxyl groups it is alsopossible to react monosaccharides together (typically by a linkagebetween the 1 and 4 carbon atoms in the reacting monosaccharides) toproduce poly-, oligo- or disaccharides. The disaccharides may be formedby the reaction between two identical monosaccharides as in maltose ortwo different monosaccharides as in sucrose and lactose.

[0014] The oligosaccharides typically comprise from 2 to 10monosaccharide units. If the oligosaccharide contains only one type ofmonosaccharide it is a homopolymer, and if the oligosaccharide containstwo or more different monosaccharides it is a heteropolymer. Someoligosaccharides include stachyose (a tetrasaccharide), maltopentose (a5-membered oligosaccharide) and cyclomaltohexaose (a 6-membered cyclicoligosaccharide).

[0015] The polysaccharides contain higher numbers of monosaccharideunits. The polysaccharides may be linear or branched. In the backbone ofthe polysaccharide the linkages between monosaccharide units aretypically between the 1-carbon and the 4-carbon of adjacentmonosaccharide units. The branches are joined to the backbone through1-carbon (on first monosaccharide on the branch) to 6-carbon (pendantfrom the monosaccharide of the backbone). Polysaccharides comprisingonly one type of monosaccharide unit are homoglycans. Polysaccharidescomprising two or more monosaccharides are heteroglycans. Heteroglycansmay be characterized by the number of different monosaccharide units inthe polymer. Polymers of two different monosaccharides arediheteroglycans. Polymers of three different monosaccharides aretriheteroglycans. Common unbranched (linear) polysaccharides includecellulose and amylose. A common branched polysaccharide is amylopectin.Cellulose, amylose and amylopectin are all homoglycans. Starch is amixture of amylose (linear polysaccharide) and amylopectin (a branchedpolysaccharide) in a weight ratio of about 25 to 85 weight % of linearpolysaccharide and 75 to 15 weight % of branched polysaccharide. Waxystarch consists essentially of branched polysaccharides.

[0016] In treating the aluminoxane in accordance with the presentinvention, the weight ratio of carbohydrate to aluminoxane may be from1:100 to 100:1, preferably from 1:25 to 25:1. The temperature of thetreatment may be from 0° C. to 200° C. Typically the temperature isabove 20° C.

[0017] The treatment may be for a time of at least 5 minutes up to 24hours. The treatment may be as long as several (e.g. 3 to 5 or more)days. Typically the time of treatment is from about 30 minutes to 16hours. Generally, the treatment takes place in an inert diluent orsolvent preferably under an inert atmosphere, preferably nitrogen. Careshould be taken to avoid contacting the aluminoxane with water.

[0018] After treatment, the aluminoxane may be treated to removeinsoluble carbohydrate. However, there may be some instances where thecarbohydrate is soluble or of a particle size which will notdetrimentally affect the polymerization. If the aluminoxane is treatedto remove insoluble carbohydrate it may typically be filtered ordecanted. The resulting aluminoxane (filtrate or decantate) may then beused in the polymerization reaction.

[0019] Aluminoxane may be used with transition metal catalysts for thepolymerization of olefins. The transition metal may be an early or latetransition metal. Some transition metals are Ti, V, Zr, Hf, Cr, Fe, Co,Ni and Pd.

[0020] Typically the catalysts used with the aluminoxane, prepared inaccordance with the present invention, comprise a transition metalcomplex of at least one C₅₋₁₃ ligand containing a 5-membered carbon ringhaving delocalized bonding within the ring and bound to the metal atomthrough covalent η¹⁵ bonds; and said ligand being unsubstituted or up tofully substituted with one or more substituents as described below.

[0021] Generally the catalyst may be a single site type catalysttypically comprising a transition metal, preferably an early transitionmetal (e.g. Ti, V, Zr and Hf) and generally having two bulky ligands. Inmany of the well known single site catalysts typically one of the bulkyligands is a cyclopentadienyl-type ligand. These cyclopentadienyl-typeligands comprise a C₅₋₁₃ ligand containing a 5-membered carbon ringhaving delocalized bonding within the ring and bound to the metal atomthrough covalent η⁵ bonds which are unsubstituted or may be furthersubstituted (sometimes referred to in a short form as Cp ligands).Cyclopentadienyl-type ligands include unsubstituted cyclopentadienyl,substituted cyclopentadienyl, unsubstituted indenyl, substitutedindenyl, unsubstituted fluorenyl and substituted fluorenyl. An exemplarylist of substituents for a cyclopentadienyl-type ligand includes thegroup consisting of C₁₋₁₀ hydrocarbyl radicals (including phenyl andbenzyl radicals), which hydrocarbyl substituents are unsubstituted orfurther substituted by one or more substituents selected from the groupconsisting of a halogen atom, preferably a chlorine or fluorine atom anda C₁₋₄ alkyl radical; a C₁₋₈ alkoxy radical; a C₆₋₁₀ aryl or aryloxyradical; an amido radical which is unsubstituted or substituted by up totwo C₁₋₈ alkyl radicals; a phosphido radical which is unsubstituted orsubstituted by up to two C₁₋₈ alkyl radicals; silyl radicals of theformula —Si—(R)₃ wherein each R is independently selected from the groupconsisting of hydrogen, a C₁₋₈ alkyl or alkoxy radical, and C₆₋₁₀ arylor aryloxy radicals; and germanyl radicals of the formula Ge—(R)₃wherein R is as defined directly above.

[0022] If there are two such bulky ligands (i.e. bis Cp) the catalystsare metallocene-type catalysts. The Cp ligand may be bridged to anotherCp ligand by a silyl bridge or a short chain (C₁₋₄) alkyl radical. TheCp-type ligand may be bridged to an amido radical which may be furthersubstituted by up to two additional substituents. Such bridged complexesare sometimes referred to as constrained geometry catalysts.

[0023] Broadly, the transition metal complex (or catalyst) suitable foruse in the present invention has the formula:

(L)_(n) —M—(X)_(p)

[0024] wherein M is a transition metal preferably selected from Ti, Hfand Zr (as described below); L is a monoanionic ligand selected from thegroup consisting of a cyclopentadienyl-type ligand, a bulky heteroatomligand (as described below) and a phosphinimine ligand (as describedbelow); X is an activatable ligand which is most preferably a simplemonoanionic ligand such as alkyl or a halide (as described below); n maybe from 1 to 3, preferably 2 or 3; and p may be from 1 to 3, preferably1 or 2, provided that the sum of n+p equals the valence state of M, andfurther provided that two L ligands may be bridged by a silyl radical ora C₁₋₄ alkyl radical.

[0025] If one or more of the L ligands is a phosphinimine ligand thetransition metal complex may be of the formula:

[0026] wherein M is a transition metal preferably selected from Ti, Hfand Zr (as described below); Pl is a phosphinimine ligand (as describedbelow); L is a monoanionic ligand selected from the group consisting ofa cyclopentadienyl-type ligand or a bulky heteroatom ligand (asdescribed below); X is an activatable ligand which is most preferably asimple monoanionic ligand such as an alkyl or a halide (as describedbelow); m is 1 or 2; n is 0 or 1; and p is an integer fixed by thevalence of the metal M (i.e. the sum of m+n+p equals the valence stateof M).

[0027] In one embodiment the catalysts are Group 4 metal complexes inthe highest oxidation state. For example, the catalyst may be a bis(phosphinimine) dichloride complex of titanium, zirconium or hafnium.Alternately, the catalyst contains one phosphinimine ligand, one “L”ligand (which is most preferably a cyclopentadienyl-type ligand) and two“X” ligands (which are preferably both chloride).

[0028] The preferred metals (M) are from Group 4, (especially titanium,hafnium or zirconium) with titanium being most preferred.

[0029] The catalyst may contain one or two phosphinimine ligands whichare covalently bonded to the metal. The phosphinimine ligand is definedby the formula:

[0030] wherein each R³ is independently selected from the groupconsisting of a hydrogen atom; a halogen atom; C₁₋₂₀, preferably C₁₋₁₀hydrocarbyl radicals which are unsubstituted by or further substitutedby a halogen atom; a C₁₋₈ alkoxy radical; a C₆₋₁₀ aryl or aryloxyradical; an amido radical; a silyl radical of the formula:

—Si—(R²)₃

[0031] wherein each R² is independently selected from the groupconsisting of hydrogen, a C₁₋₈ alkyl or alkoxy radical, and C₆₋₁₀ arylor aryloxy radicals; and a germanyl radical of the formula:

Ge—(R²)₃

[0032] wherein R² is as defined above.

[0033] The preferred phosphinimines are those in which each R³ is ahydrocarbyl radical, preferably a C₁₋₆ hydrocarbyl radical.

[0034] Preferred phosphinimine catalysts are Group 4 organometalliccomplexes which contain one phosphinimine ligand (as described above)and one ligand L which is either a cyclopentadienyl-type ligand or aheteroligand.

[0035] As used herein, the term “heteroligand” refers to a ligand whichcontains at least one heteroatom selected from the group consisting ofboron, nitrogen, oxygen, phosphorus or sulfur. The heteroligand may besigma or pi-bonded to the metal. Exemplary heteroligands includeketimide ligands, silicone-containing heteroligands, amido ligands,alkoxy ligands, boron hetrocyclic ligands and phosphole ligands, as alldescribed below.

[0036] As used herein, the term “ketimide ligand” refers to a ligandwhich:

[0037] (a) is bonded to the transition metal via a metal-nitrogen atombond;

[0038] (b) has a single substituent on the nitrogen atom, (where thissingle substituent is a carbon atom which is doubly bonded to the Natom); and

[0039] (c) has two substituents Sub 1 and Sub 2 (described below) whichare bonded to the carbon atom.

[0040] Conditions a, b and c are illustrated below:

[0041] The substituents “Sub 1” and “Sub 2” may be the same ordifferent. Exemplary substituents include hydrocarbyls having from 1 to20 carbon atoms, silyl groups, amido groups and phosphido groups. Forreasons of cost and convenience it is preferred that these substituentsboth be hydrocarbyls, especially simple alkyls and most preferablytertiary butyl.

[0042] Silicon containing hetroligands are defined by the formula:

—(μ)SiR_(x)R_(y)R_(z)

[0043] wherein the—denotes a bond to the transition metal and μ issulfur or oxygen.

[0044] The substituents on the Si atom, namely R_(x), R_(y) and R_(z)are required in order to satisfy the bonding orbital of the Si atom. Theuse of any particular substituent R_(x), R_(y) or R_(z) is notespecially important to the success of this invention. It is preferredthat each of R_(x), R_(y) and R_(z) is a C₁₋₂ hydrocarbyl group (i.e.methyl or ethyl) simply because such materials are readily synthesizedfrom commercially available materials.

[0045] The term “amido” is meant to convey its broad, conventionalmeaning. Thus, these ligands are characterized by (a) a metal-nitrogenbond and (b) the presence of two substituents (which are typicallysimple alkyl or silyl groups) on the nitrogen atom.

[0046] The terms “alkoxy” and “aryloxy” is also intended to convey itsconventional meaning. Thus, these ligands are characterized by (a) ametal oxygen bond and (b) the presence of a hydrocarbyl group bonded tothe oxygen atom. The hydrocarbyl group may be a C₁₋₁₀ straight chained,branched or cyclic alkyl radical or a C₆₋₁₃ aromatic radical whichradicals are unsubstituted or further substituted by one or more C₁₋₄alkyl radicals (e.g. 2, 6 di-tertiary butyl phenoxy).

[0047] Boron heterocyclic ligands are characterized by the presence of aboron atom in a closed ring ligand. This definition includesheterocyclic ligands which also contain a nitrogen atom in the ring.These ligands are well known to those skilled in the art of olefinpolymerization and are fully described in the literature (see, forexample, U.S. Pat. Nos. 5,637,659; 5,554,775 and the references citedtherein).

[0048] The term “phosphole” is also meant to convey its conventionalmeaning. “Phospholes” are cyclic dienyl structures having four carbonatoms and one phosphorus atom in the closed ring. The simplest phospholeis C₄PH₄ (which is analogous to cyclopentadiene with one carbon in thering being replaced by phosphorus). The phosphole ligands may besubstituted with, for example, C₁₋₂₀ hydrocarbyl radicals (which may,optionally, contain halogen substituents); phosphido radicals; amidoradicals; or silyl or alkoxy radicals. Phosphole ligands are also wellknown to those skilled in the art of olefin polymerization and aredescribed as such in U.S. Pat. No. 5,434,116 (Sone, to Tosoh).

[0049] The term “activatable ligand” or “leaving ligand” refers to aligand which may be activated by the aluminoxane, (also referred to asan “activator”), to facilitate olefin polymerization. Exemplaryactivatable ligands are independently selected from the group consistingof a hydrogen atom; a halogen atom, preferably a chlorine or fluorineatom; a C₁₋₁₀ hydrocarbyl radical, preferably a C₁₋₄ alkyl radical; aC₁₋₁₀ alkoxy radical, preferably a C₁₋₄ alkoxy radical; and a C₅₋₁₀ aryloxide radical; each of which said hydrocarbyl, alkoxy, and aryl oxideradicals may be unsubstituted by or further substituted by one or moresubstituents selected from the group consisting of a halogen atom,preferably a chlorine or fluorine atom; a C₁₋₈ alkyl radical, preferablya C₁₋₄ alkyl radical; a C₁₋₈ alkoxy radical, preferably a C₁₋₄ alkoxyradical; a C₆₋₁₀ aryl or aryloxy radical; an amido radical which isunsubstituted or substituted by up to two C₁₋₈, preferably C₁₋₄ alkylradicals; and a phosphido radical which is unsubstituted or substitutedby up to two C₁₋₈, preferably C₁₋₄ alkyl radicals.

[0050] The number of activatable ligands depends upon the valency of themetal and the valency of the activatable ligand. The preferred catalystmetals are Group 4 metals in their highest oxidation state (i.e. 4⁺) andthe preferred activatable ligands are monoanionic (such as ahalide—especially chloride or C₁₋₄ alkyl—especially methyl). One usefulgroup of catalysts contain a phosphinimine ligand, a cyclopentadienylligand and two chloride (or methyl) ligands bonded to the Group 4 metal.In some instances, the metal of the catalyst component may not be in thehighest oxidation state. For example, a titanium (III) component wouldcontain only one activatable ligand.

[0051] As noted above, one group of catalysts is a Group 4organometallic complex in its highest oxidation state having aphosphinimine ligand, a cyclopentadienyl-type ligand and two activatableligands. These requirements may be concisely described using thefollowing formula for the preferred catalyst:

[0052] wherein: M is a metal selected from Ti, Hf and Zr; Pl is asdefined above, but preferably a phosphinimine wherein R³ is a C₁₋₆ alkylradical, most preferably a t-butyl radical; L is a ligand selected fromthe group consisting of cyclopentadienyl, indenyl and fluorenyl ligandswhich are unsubstituted or substituted by one or more substituentsselected from the group consisting of a halogen atom, preferablychlorine or fluorine; C₁₋₄ alkyl radicals; and benzyl and phenylradicals which are unsubstituted or substituted by one or more halogenatoms, preferably fluorine; X is selected from the group consisting of achlorine atom and C₁₋₄ alkyl radicals; m is 1; n is 1; and p is 2.

[0053] In one embodiment of the present invention the transition metalcomplex may have the formula: [(Cp)_(q)M[N=P(R³)]_(b)X_(c) wherein M isthe transition metal; Cp is a C₅₋₁₃ ligand containing a 5-memberedcarbon ring having delocalized bonding within the ring and bound to themetal atom through covalent η⁵ bonds and said ligand being unsubstitutedor up to fully substituted with one or more substituents selected fromthe group consisting of a halogen atom, preferably chlorine or fluorine;C₁₋₄ alkyl radicals; and benzyl and phenyl radicals which areunsubstituted or substituted by one or more halogen atoms, preferablyfluorine; R³ is a substituent selected from the group consisting ofC₁₋₁₀ straight chained or branched alkyl radicals, C₆₋₁₀ aryl andaryloxy radicals which are unsubstituted or may be substituted by up tothree C₁₋₄ alkyl radicals, and silyl radicals of the formula —Si—(R)₃wherein R is C₁₋₄ alkyl radical or a phenyl radical; L is selected fromthe group consisting of a leaving ligand; q is 1 or 2; b is 1 or 2; andthe valence of the transition metal—(q+b)=c.

[0054] The polymerization in accordance with the present invention maybe conducted in a liquid phase as either a slurry or solutionpolymerization conducted in an inert diluent or solvent, or a gas phasepolymerization. The difference between slurry and solutionpolymerization being whether the resulting polymer is soluble in theliquid phase.

[0055] The catalyst systems of the present invention may further besupported on a refractory support or an organic support (includingpolymeric support). That is either the transition metal complex or thetreated aluminoxane compound or both may be supported on a refractorysupport or an organic support (e.g. polymeric). Some refractoriesinclude silica which may be treated to reduce surface hydroxyl groupsand alumina. The support or carrier may be a spray-dried silica.Generally the support will have an average particle size from about 0.1to about 1000, preferably from about 10 to 150 microns. The supporttypically will have a surface area of at least about 50 m²/g, preferablyfrom about 150 to 1500 m²/g. The pore volume of the support should be atleast 0.2, preferably greater than 0.6 cm³/g.

[0056] If the support is silica it may be dried by heating at atemperature of at least about 100° C., for at least 2 hours, preferablyfrom about 2 to 24 hours under an inert atmosphere. In an alternatetreatment, the excess surface hydroxyl radicals may be removed bychemical reaction with a reactive species. Suitable reactive speciesinclude metal alkyls, including magnesium alkyls, lithium alkyls andaluminum alkyls. It should be noted that as the carbohydrate used inaccordance with the present invention could react with metal alkyls, thesupport should be treated with the metal alkyls prior to contact withthe aluminoxane. It is also reasonably apparent to one skilled in theart if the silica has been treated with metal alkyls a carryover of somecarbohydrate (e.g. soluble carbohydrate) may also remove any free metalalkyls which may be present (adsorbed) on the support.

[0057] Solution and slurry polymerization processes are fairly wellknown in the art. These processes are conducted in the presence of aninert hydrocarbon solvent typically a C₄₋₁₂ hydrocarbon which may beunsubstituted or substituted by a C₁₋₄ alkyl group such as butane,pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane orhydrogenated naphtha. An additional solvent is Isopar E (C₈₋₁₂ aliphaticsolvent, Exxon Chemical Co.).

[0058] The polymerization may be conducted at temperatures from about20° C. to about 250° C. Depending on the product being made, thistemperature may be relatively low such as from 20° C. to about 180° C.,typically from about 80° C. to 150° C. and the polymer is insoluble inthe liquid hydrocarbon phase (diluent) (e.g. a slurry polymerization).The reaction temperature may be relatively higher from about 180° C. to250° C., preferably from about 180° C. to 230° C. and the polymer issoluble in the liquid hydrocarbon phase (solvent). The pressure of thereaction may be as high as about 15,000 psig for the older high pressureprocesses or may range from about 15 to 4,500 psig.

[0059] In the gas phase polymerization of a gaseous mixture comprisingfrom 0 to 15 mole % of hydrogen, from 0 to 30 mole % of one or more C₃₋₈alpha-olefins, from 15 to 100 mole % of ethylene, and from 0 to 75 mole% of an inert gas at a temperature from 50° C. to 120° C., preferablyfrom 75° C. to about 110° C., and at pressures typically not exceeding3447 kPa (about 500 psi), preferably not greater than 2414 kPa (about350 psi).

[0060] Suitable olefin monomers may be ethylene and C₃₋₂₀ mono- and di-olefins. Preferred monomers include ethylene and C₃₋₁₂ alpha olefinswhich are unsubstituted or substituted by up to two C₁₋₆ alkyl radicals.Illustrative non-limiting examples of such alpha olefins are one or moreof propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and1-decene. The polymers prepared in accordance with the present inventionhave a good molecular weight. That is, weight average molecular weight(Mw) will preferably be greater than about 30,000 ranging up to 10⁷,preferably 10⁵ to 10⁷. Hydrogen may be used in the polymerization tocontrol the molecular weight of the polymer.

[0061] The polyethylene polymers which may be prepared in accordancewith the present invention typically comprise not less than 60,preferably not less than 70, most preferably not less than 80, weight %of ethylene and the balance of one or more C₄₋₁₀ alpha olefins,preferably selected from the group consisting of 1-butene, 1-hexene and1-octene.

[0062] The present invention will now be illustrated by the followingnon-limiting examples. In the examples unless otherwise indicated partsmeans part by weight (i.e. grams) and percent means weight percent.

EXAMPLES

[0063] Catalyst Preparation

[0064] Catalyst 1

[0065] In a round bottom flask, 2.0 g of silica (Davison XPO-2408),dehydrated at 200° C. in air for 2 hours and at 600° C. under nitrogenfor 6 hours was slurried in approximately 10 mL of dried toluene. 2.42 gof an aluminoxane (methyl) solution (13.75 weight % Al in toluene) wasadded into the flask. The slurry was stirred overnight at roomtemperature. 46 mg of tri-tert-butyl phosphiniminate indenyl titaniumdichloride was dissolved in 10 mL of toluene and added slowly into theslurry which was subsequently stirred for 2 hours at room temperatureand further for 2 hours at 45° C. The solvent was removed by filtrationand the solid washed three times with n-hexane and vacuum dried.

[0066] Catalyst 2

[0067] The procedure followed is the same as Catalyst 1, except that thealuminoxane solution used in this catalyst preparation was pre-treatedwith cellulose by stirring 12.1 g of the aluminoxane solution with 0.5 gof cellulose overnight at room temperature, followed by the removal ofcellulose by filtration.

[0068] Catalyst 3

[0069] The procedure followed is the same as Catalyst 2, except that 1.0g of cellulose was used to pre-treat 12.1 g of the aluminoxane solution.

Polymerization Results

[0070] Polymerization 1

[0071]160 g of NaCl was added into a 2-litre autoclave reactor for useas a seedbed. The reactor was heated to 100° C. and thoroughly purgedwith ethylene gas. Approximately 0.40 mL of tri-isobutyl aluminum inn-hexane solution (0.40 mmol) and 3 mL of 1-hexene were injected intothe reactor. After the reactor was cooled down to 90° C. and pressurizedwith 100 psig ethylene, 9 mg of Catalyst 1 was added and the reactor waspressurized with 200 psig ethylene. The polymerization proceeded for 60minutes with the temperature maintained at 90° C. and the pressure at200 psig. The reaction was terminated by rapidly venting the reactiongases and cooling the reactor to room temperature. The polymer yield was38.0 g.

[0072] Polymerization 2

[0073] The reaction was carried out as in Polymerization 1, except that10 mg of Catalyst 2 was used instead of 9 mg Catalyst 1. The polymeryield was 50.0 g.

[0074] Polymerization 3

[0075] The reaction was carried out as in Polymerization 1, except that8 mg of Catalyst 3 was used instead of 9 mg of Catalyst 1. The polymeryield was 45.6 g.

What is claimed is:
 1. A process comprising treating a complex aluminumcompound of the formula R⁴ ₂AlO(R⁴AlO)_(m)AlR⁴ ₂ wherein each R⁴ isindependently selected from the group consisting of C₁₋₂₀ hydrocarbylradicals and m is from 3 to 50, with one or more carbohydrates in aweight ratio of aluminum complex to carbohydrate from 1:100 to 100:1 ata temperature from 0° C. to 200° C. for a time of at least 5 minutes. 2.The process according to claim 1, wherein the carbohydrate is selectedfrom the group consisting of monosaccharides and polysaccharides.
 3. Theprocess according to claim 2, wherein in the aluminum complex R⁴ is aC₁₋₄ alkyl radical and m is from 5 to
 30. 4. The process according toclaim 3, wherein the weight ratio of aluminum complex to carbohydrate isfrom 1:25 to 25:1.
 5. The process according to claim 4, wherein thecarbohydrate is a C₃₋₆ monosaccharide.
 6. The process according to claim4, wherein the carbohydrate is a polysaccharide.
 7. The processaccording to claim 6, wherein the polysaccharide is a homoglycanpolysaccharide.
 8. The process according to claim 7, wherein thehomoglycan polysaccharide is unbranched.
 9. The process according toclaim 8, wherein the homoglycan polysaccharide is cellulose.
 10. Acatalyst system comprising a transition metal complex in the presence ofan activator comprising a complex aluminum compound of the formula R⁴₂AlO(R⁴AlO)_(m)AlR⁴ ₂ wherein each R⁴ is independently selected from thegroup consisting of C₁₋₂₀ hydrocarbyl radicals and m is from 3 to 50which has been treated with one or more carbohydrates in a weight ratioof aluminum complex to carbohydrate from 1:100 to 100:1 at a temperaturefrom 0° C. to 200° C., to provide a molar ratio of treated aluminum totransition metal from 5:1 to 1000:1.
 11. The catalyst system accordingto claim 10, wherein the transition metal is selected from the groupconsisting of Ti, V, Zr, Hf, Cr, Fe, Co, Ni and Pd.
 12. The catalystsystem according to claim 11, wherein the catalyst has the formula:(L)_(n)—M—(X)_(p) wherein M is a transition metal; L is a monoanionicligand selected from the group consisting of a cyclopentadienyl-typeligand, a bulky heteroatom ligand and a phosphinimine ligand; X is anactivatable ligand; n may be from 1 to 3; and p may be from 1 to 3,provided that the sum of n+p equals the valence state of M, and furtherprovided that two L ligands may be bridged by a silyl radical or a C₁₋₄alkyl radical.
 13. The catalyst system according to claim 12, whereinthe cyclopentadienyl-type ligand is a C₅₋₁₃ ligand containing a5-membered carbon ring having delocalized bonding within the ring andbound to the metal atom through covalent η⁵ bonds and said ligand beingunsubstituted or up to fully substituted with one or more substituentsselected from the group consisting of C₁₋₁₀ hydrocarbyl radicals inwhich hydrocarbyl substituents are unsubstituted or further substitutedby one or more substitutents selected from the group consisting of ahalogen atom and a C₁₋₄ alkyl radical; a halogen atom; a C₁₋₈ alkoxyradical; a C₆₋₁₀ aryl or aryloxy radical; an amido radical which isunsubstituted or substituted by up to two C₁₋₈ alkyl radicals; aphosphido radical which is unsubstituted or substituted by up to twoC₁₋₈ alkyl radicals; silyl radicals of the formula —Si—(R)₃ wherein eachR is independently selected from the group consisting of hydrogen, aC₁₋₈ alkyl or alkoxy radical, and C₆₋₁₀ aryl or aryloxy radicals; andgermanyl radicals of the formula Ge—(R)₃ wherein R is as defined above.14. The catalyst system according to claim 13, wherein X is selectedfrom the group consisting of a hydrogen atom; a halogen atom, preferablya chlorine or fluorine atom; a C₁₋₁₀ hydrocarbyl radical; a C₁₋₁₀ alkoxyradical; a C₅₋₁₀ aryl oxide radical; each of which said hydrocarbyl,alkoxy, and aryl oxide radicals may be unsubstituted by or furthersubstituted by one or more substituents selected from the groupconsisting of a halogen atom; a C₁₋₈ alkyl radical; a C₁₋₈ alkoxyradical; a C₆₋₁₀ aryl or aryloxy radical; an amido radical which isunsubstituted or substituted by up to two C₁₋₈ alkyl radicals; and aphosphido radical which is unsubstituted or substituted by up to twoC₁₋₈ alkyl radicals.
 15. The catalyst system according to claim 14,wherein the transition metal complex has the formula:

wherein M is a transition metal; Pl is a phosphinimine ligand; L is amonoanionic ligand selected from the group consisting of acyclopentadienyl-type ligand or a bulky heteroatom ligand; X is anactivatable ligand; m is 1 or 2; n is 0 or 1; and p is an integer andthe sum of m+n+p equals the valence state of M.
 16. The catalyst systemaccording to claim 15, wherein the cyclopentadienyl-type ligand isselected from the group consisting of a cyclopentadienyl radical, anindenyl radical and a fluorenyl radical which radicals are unsubstitutedor up to fully substituted by one or more substituents selected from thegroup consisting of a fluorine atom, a chlorine atom; C₁₋₄ alkylradicals; and a phenyl or benzyl radical which is unsubstituted orsubstituted by one or more fluorine atoms.
 17. The catalyst systemaccording to claim 16, wherein in the aluminum complex R⁴ is selectedfrom the group consisting of C₁₋₄ alkyl radicals and m is from 5 to 30.18. The catalyst system according to claim 17, wherein the carbohydrateis a C₃₋₆ monosaccharide.
 19. The catalyst system according to claim 17,wherein the carbohydrate is a polysaccharide.
 20. The catalyst systemaccording to claim 19, wherein the polysaccharide is a homoglycanpolysaccharide.
 21. The catalyst system according to claim 20, whereinthe homoglycan polysaccharide is unbranched.
 22. The catalyst systemaccording to claim 21, wherein the homoglycan polysaccharide iscellulose.
 23. The catalyst system according to claim 10, furthercomprising a support.
 24. The catalyst system according to claim 23,wherein the support is silica.
 25. The catalyst system according toclaim 18, further comprising a support.
 26. The catalyst systemaccording to claim 25, wherein the support to silica.
 27. The catalystsystem according to claim 19, further comprising a support.
 28. Thecatalyst system according to claim 27, wherein the support to silica.29. The catalyst system according to claim 20, further comprising asupport.
 30. The catalyst system according to claim 29, wherein thesupport is silica.
 31. The catalyst system according to claim 21,further comprising a support.
 32. The catalyst system according to claim31, wherein the support is silica.
 33. The catalyst system according toclaim 22, further comprising a support.
 34. The catalyst systemaccording to claim 33, wherein the support is silica.
 35. The catalystsystem according to claim 12, wherein in the aluminum complex R⁴ isselected from the group consisting of C₁₋₄ alkyl radicals and m is from5 to
 30. 36. The catalyst system according to claim 35, wherein thecarbohydrate is a C₃₋₆ monosaccharide.
 37. The catalyst system accordingto claim 35, wherein the carbohydrate is a polysaccharide.
 38. Thecatalyst system according to claim 37, wherein the polysaccharide is ahomoglycan polysaccharide.
 39. The catalyst system according to claim38, wherein the homoglycan polysaccharide is unbranched.
 40. Thecatalyst system according to claim 39, wherein the homoglycanpolysaccharide is cellulose.
 41. The catalyst system according to claim12, further comprising a support.
 42. The catalyst system according toclaim 41, wherein the support is silica.
 43. The catalyst systemaccording to claim 36, further comprising a support.
 44. The catalystsystem according to claim 43, wherein the support to silica.
 45. Thecatalyst system according to claim 37, further comprising a support. 46.The catalyst system according to claim 45, wherein the support tosilica.
 47. The catalyst system according to claim 38, furthercomprising a support.
 48. The catalyst system according to claim 47,wherein the support is silica.
 49. The catalyst system according toclaim 39, further comprising a support.
 50. The catalyst systemaccording to claim 49, wherein the support is silica.
 51. The catalystsystem according to claim 40, further comprising a support.
 52. Thecatalyst system according to claim 51, wherein the support is silica.53. A process for the polymerization of a mixture comprising from 80 to100 weight % of ethylene and from 0 to 20 weight % of one or more C₃₋₈alpha olefins at a temperature from 80° C. to 250° C. in the presence ofa catalyst system according to claim
 10. 54. A process for thepolymerization of a mixture comprising from 80 to 100 weight % ofethylene and from 0 to 20 weight % of one or more C₃₋₈ alpha olefins ata temperature from 80° C. to 250° C. in the presence of a catalystsystem according to claim
 12. 55. A process for the polymerization of amixture comprising from 80 to 100 weight % of ethylene and from 0 to 20weight % of one or more C₃₋₈ alpha olefins at a temperature from 80° C.to 250° C. in the presence of a catalyst system according to claim 18.56. A process for the polymerization of a mixture comprising from 80 to100 weight % of ethylene and from 0 to 20 weight % of one or more C₃₋₈alpha olefins at a temperature from 80° C. to 250° C. in the presence ofa catalyst system according to claim
 19. 57. A process for thepolymerization of a mixture comprising from 80 to 100 weight % ofethylene and from 0 to 20 weight % of one or more C₃₋₈ alpha olefins ata temperature from 80° C. to 250° C. in the presence of a catalystsystem according to claim
 24. 58. A process for the polymerization of amixture comprising from 80 to 100 weight % of ethylene and from 0 to 20weight % of one or more C₃₋₈ alpha olefins at a temperature from 80° C.to 250° C. in the presence of a catalyst system according to claim 26.59. A process for the polymerization of a mixture comprising from 80 to100 weight % of ethylene and from 0 to 20 weight % of one or more C₃₋₈alpha olefins at a temperature from 80° C. to 250° C. in the presence ofa catalyst system according to claim
 28. 60. A process for thepolymerization of a mixture comprising from 80 to 100 weight % ofethylene and from 0 to 20 weight % of one or more C₃₋₈ alpha olefins ata temperature from 80° C. to 250° C. in the presence of a catalystsystem according to claim
 12. 61. A process for the polymerization of amixture comprising from 80 to 100 weight % of ethylene and from 0 to 20weight % of one or more C₃₋₈ alpha olefins at a temperature from 80° C.to 250° C. in the presence of a catalyst system according to claim 36.62. A process for the polymerization of a mixture comprising from 80 to100 weight % of ethylene and from 0 to 20 weight % of one or more C₃₋₈alpha olefins at a temperature from 80° C. to 250° C. in the presence ofa catalyst system according to claim
 37. 63. A process for thepolymerization of a mixture comprising from 80 to 100 weight % ofethylene and from 0 to 20 weight % of one or more C₃₋₈ alpha olefins ata temperature from 80° C. to 250° C. in the presence of a catalystsystem according to claim
 42. 64. A process for the polymerization of amixture comprising from 80 to 100 weight % of ethylene and from 0 to 20weight % of one or more C₃₋₈ alpha olefins at a temperature from 80° C.to 250° C. in the presence of a catalyst system according to claim 44.65. A process for the polymerization of a mixture comprising from 80 to100 weight % of ethylene and from 0 to 20 weight % of one or more C₃₋₈alpha olefins at a temperature from 80° C. to 250° C. in the presence ofa catalyst system according to claim 47.